Wing mounted defensive units for airplanes



March 13, 1956 GRAVENHORST ET AL 2,737,853

WING MOUNTED DEFENSIVE UNITS FOR AIRPLANES 2 Sheets-Sheet 1 Filed July 15, 1949 INVENTORS 144 54%1,

March 13, 1956 GRAVENHQRST ET AL 2,737,853

WING MOUNTED DEFENSIVE UNITS FOR AIRPLANES Filed July 15, 1949 2 Sheets-Sheet 2 WING.MOUNTED DEFENSIVE UNITS FOR AIRPLANES :Gordou P. Gravenhorst, Middle River, and Talmadge W.

Elam,.Raspeburg, Md., assignors to The Glenn L. Mar- Cornpany, .Middle River, .Md., a corporation of Maryland Application July 15, 1949, Serial No. 104,914

invention relates to improved defensive units for airplanes and particularly to a novel arrangement of such units wherein they are mounted at the tips of the -ivin'gs'of the airplane to provide complete spherical defensecoverage.

' Modern-day bombing aircraft are capable of covering *suchgreat-distances and at such relatively high speeds 'thatthey are at the present time required to he substantially self-sufiicient in that they can no longer rely upon fighter aircraft to protect them from enemy aircraft. It is; therefore, imperative that such bombing aircraft ---be provided with armament capable of giving full spherifical fire-coverage as well as that they be provided with l'suitable search radar equipment for detecting any enemy :aircraft in their general'vicinity. To be most effective, r suchsradarcoverage must also. be substantially spherical. eUp to :the present time, attempts to obtain such coverage z-have resulted in: providing a .plurality of gun turrets 'tmountedii-at various .pointson the fuselage and pro- :ftrudingzthemfrominto the slip stream and alsoin proryidingrradar scanners located in radomesalso projecting ,.-:into'.theslip stream,-with the result that rather great drag has been produced. Moreovergthe location of'the tur- ;;rets.s,and radarunits on J the fuselage has necessitated *ratherzcomplicated' apparatus toprevent interference by -;the;projecting portions-of the airplane itself.

.EIt is; an object of'theppresentinvention to provide an 3 arrangement of gun turrets and radar scanning units which will provide for full spherical coverage withthe minimum of drag.

lt i-s a. further -object to -provide a.v pair of compact r-streamlined defensive units or housingszicarried at the extreme tips of .the wingstof an airplane,-eachqproviding iorrradar. searching-and gunfire-coverage over-at least a-fullhemisphere.

-,It ista further object to provide such an arrangement wherein said defensive units are oppositely oriented relative, ;to .the .-,direction of movement of :said aircraft-where L by'full sphericalo coverage will 'be'obtai-ned fromzxt-wo sasu'chz units, one in each wing tip.

.;lt is.. another-object of this invent-ion: togprovide=-a .;rnounting for a radar scanner within'a streamlinedihous- .ning'at the tip ofthe wing of an airplanewherein said ..scanner will be oriented so as to provide 2effectiveucover- ..age,ofa-full hemisphere ,andwhich will yet permitefiec- ..-tivestreamlini ng :of said housing.

1 A-further object is to-provide an elongated streamlined adefensive; unit at thetip: of the wing ofaniairplane,-..comuprising-a generally conical end portion housing a radar 1-.scannensoorienteditherein -as to provide hemispherical .searchcoverage, a -central portion consitituted by ahar-relt tjypegunturretrotatable aboutthe. axis of said unit; and aJs'ecbnd ,conica'l end portion including a; gun turret ni'oun'tedjn the tip thereof, said-turrets {together ,having ffir'efcove'rjage in excess of a hemisphere. Ye t a'jfu'rther object is to provide sucha defensive 'uriit in w'hichthe'two end portions are substantially syinr'netrical-whereby a similar unit .may' be reversibly arttes atent sum of. ,s11ght1y, overlapping paths, one. above theother.

2 ranged on-the opposite wing" tip to cooperate with the other. unit to give full spherical radar and fire coverage about said aircraft without producing unde'sirableyawing moments on the airplane.

Further objects and advantages willgbecome apparent from a reading of the following description and claims.

In the drawings:

Figure 1 is a somewhat diagrammatic plane view-of an airplane equipped with the defensive-wing units of the invention.

Figure 2 is a sideview of oneofthe units.

' Figure-3 is an end view looking toward the rad'ome end of one of theunits.

Figure 4 is afragmentary plan view of one of the units showing the manner'in which'it is attached to the wing. Figure 5 is aside view of the-scanning mechanism.

Figure 6 is a block diagram of the radar system employed.

Turning first to'"Figure 1, there is shown an airplane 1 having'the usual fuselageZ and laterally extending wings -barrelturret beingmounted for rotation aboutthe'long'i- -tudinal axis aa' of said-unit. Theend portion 6 includesangun turret fimounted in a well-known manner for limited swingingabout a vertical-axis v-v' and:a

horizontal axis h-h'. Guns 9 carried by the turrets are*rotatablewith'said turret about said axes so as to "have approximately 60 conical fire coverage as'clear-ly indicated :in Eigures land 2. :Barrel turret 7 carries a pair of-guns =10=angularly traversible in a plane extending generally:longtitu'dinally of the barrel turret through an angle of approximately .140. as shown in Figures 1 .and 2 androtatablewith theturret. about the axis aa' through an angle of substantially. 240 as indicated in Figure '3.

'The-;=guns' 10::extend through suitable slots 12 in the Outer,covering-tithe barrel turret. A-pair of radornes 11, for use with suitable radar-type gun directing apparacludes a radome;13; forming., he. extreme end of said As best shown in Figure 4, the wing-packages or units include stationary -.disc-like.-supportingnembers'lS rig- .idly. carried bya hollow tubular member 16 extending ,acrossthe endof-the--wing and rigidly attached to the wingspan-17. Theframeworkl8 of the barrel turret is rotatably carriedby-bearing members 19 formedon discs -15,--while housing :portions- Sand 6 are rigidly car- .ried by said 'discs 15. The skin-of the :wing is faired desired andtto furnish information to the operator in form wlnchmavhe ;'quickly and easily interpreted, to enable him to-bestplanwhat defensive action should be taken. ,In the helical scanning system, ascanning beam is caused to be successively swept rapidly through a desiredangleabouta vertical axis while at the same time,

it is causedto be slowly'tilted or nodded about ah0ri- 'zontalaxis was to cover the desiredsect0r in a succes- Sincje, it wouldfbe substantially impossible .to obtm'n full spherical coverage by a single scanner (since'the airplane structure itself would interfere), two separate scanning mechanisms are employed, each scanning slightly ,in excess of a full hemisphere, the two being arranged so designed that a scanning beam approximately six degrees in width is produced thereby. The antenna units are carried at opposite ends of a pair of arms 22, said arms being pivotally supported at their center portions for oscillation in a vertical plane about the axis of suitable bearings 23 carried at the upper end of a tubular post 24. This post 24 is supported for rotation about its vertical axis by bearings 25 and 26 carried by a support 27. Support 27 has a flange 28 by which it may be attached to suitable structure inside of the housing portion 5 to fixedly mount the scanning mechanism therein. The scanner is rotated about said vertical axis by means of a suitable motor (not shown) mounted within housing 29 and driving a shaft 30 arranged to rotate the post 24 by means of bevel gearing 31.

To oscillate or nod the arms 22 and the antenna units carried thereby about the axis of bearings 23, a sleeve 32 is slidably mounted on post 24 and is caused to rotate therewith by a suitable pin and slot connection 33. Sleeve 32, at one side thereof, is extended upwardly between the arms 22 and carries at its upper end a transverse pin 34 which extends outwardly through slots 35 formed in the arms 22. Thus, it can be seen that by reciprocating sleeve 32 relative to post 24, the arms 22 will be swung up and down about their mean position shown in Figure 5 in solid lines. Any suitable mechanism may be employed for so reciprocating sleeve 32. For example, a roller 36, carried at the outer end of a lever 37 pivotally supported at 38 from the housing 29, may be provided to engage between flanges 39 formed on the lower end of said sleeve. A second roller 40, carried by an intermediate portion of lever 37, is adapted to ride in a cam slot of a cam 41 carried by'a shaft 41 at the side of housing 29.

Shaft 41' is adapted to be rotated by suitable reduction gearing (not shown) located within the housing 29 and driven by the same motor that rotates posts 24. Shaft 41 rotates at a much slower rate than post 24 so that the scanners will make several sweeps across the sector to be scanned during each nodding cycle. The ratio will be such that the desired amount of overlap between successive sweeps will obtain.

With the arrangement so far described, the scanning coverage would not include a full 180 in a vertical plane since arms 22 may be oscillated through only about 100. In order to get full hemispherical coverage, the antenna units are pivotally mounted as shown at 42 on the outer ends of arms 22. The reflectors include gear sectors 43 adapted to be driven by suitable gearing 44 from a small electric motor 45 carried centrally by the arms 22. Actuation of the motor 45 in one direction will cause both reflectors to be swung upwardly simultaneously about their pivots 42 while rotation in the opposite direction will cause the reflectors to swing downwardly about said pivots. Motor 45 is adapted to be energized at the discretion of the operator and will be connected by suitable electric leads and slip rings (not shown), to suitable control means located at the operators station in the fuselage.

Energy is fed to and from the antennas 20 by suitable wave guides 46 and 47, one leading to each of the antenna units. As indicated in Figure 5, these wave guides will include the usual swivel connections coaxial with pivots 42 and 23. These wave guides lead downwardly through the hollow interior of post 24 and outwardly through suitable openings in the side thereof between bearings 25 and 26. The lower ends of these wave guides are turned inwardly as shown in Figure 5 to couple with a suitable radio frequency switch. This switch is shown as comprising a T section of wave guide 48 also arranged to rotate with said post and having the ends 49 of its cross portion lying closely adjacent and directly opposite the corresponding open ends of wave guides 46 and 47 in energy coupling relation therewith. Rigidly carried by the bearing 26 is a stationary semicylindrical shield 50 arranged to extend into thespace between the ends of the T section and the corresponding ends of wave guides 46 and 47 to alternately prevent coupling therebetween during successive 180 of rotaticn as the scanning mechanism rotates about the axis of post 24. The shield 50 is so positioned that, at any particular time, the wave guide 46 or 47 associated with the antenna. unit sweeping through the 180 lying opposite from the mounting support 27'at that particular time, will be coupled with the T section 48 while the wave guide associated with the other antenna unit will be effectively blocked by the shield. Energy is fed to T section 48 by means of stationary wave guide section 51 having a suitable swivel connection therewith coaxial with the axis of rotation of post 24.

The parts are proportioned so that'for any particular adjustment of the antenna units relative .to arms .22 the scanner will automatically scan a sector of space extending approximately 180 in azimuth about the axis of post 24 and extending approximately v in elevation about the axis of bearings 23. With the antenna units adjusted as shown in solid lines in Figure 5 relative to arms 22, the sector will extend substantiallySO above and 50 below a horizontal plane through the axis of bearings 23. Actually, since the scanning beam itself has a width of approximately 6, the angular extent of the sector scanned will be slightly greater than the above, as clearly indicated in Figure 1.

By energizing motor 45 to cause rotation thereof in the desired direction, the antenna units may be adjusted relative to bars 22 through a vertical angle of 40 in either direction from their position shown in full lines in Figure 5, to shift the sector to be automatically scanned relative to the airplane. Thus by tilting both antenna units downwardly 40 relative to the arms 22, the sector of space scanned will extend from directly below the airplane to about 10 above a horizontal plane through the scanner as indicated 'at p" in Figure 2. Conversely by tilting the antenna units upwardly relative to the arms 22, the sector scanned will extend from about 10 below the horizontal to a point directly above the airplane as indicated at p in Figure 2.

Thus with the arrangement shown, it can readily be seen that each scanning mechanism 14 is adapted to sub stantially completely scan the hemispherical sector of space lying to one side of a vertical reference plane passing through the axis of post 24. As indicated in Figure 1, the scanners are so oriented in their housing portions 5 as to be able to scan the hemispherical sectors lying outwardly from the airplane beyond their reference planes A--A' and BB', which reference planes lie substantially parallel and at an angle a relative to the intersect said axis beyond but relatively adjacent the longitudinal axis of the airplane fuselage such that they corresponding ends of the fuselage. While these reference planes are spaced slightly relative to one another,

it should be remembered that the actual sectors scanned will extend slightly inwardly beyond their corresponding planes due to the angular divergence of the scanning beam itself as shown in Figure 1. The sectors scanned by the two oppositely disposed scanning units will therefore converge and intersect at some predetermined .dis tange outwardly from' the airplane. Beyond that distance, full spherical scanning coverage will, therefore, be provided from any-objects lying" within the's'ect'ors searchedoy theassociatedscanners is applied to a conventionalP; P5 I. scope SG, control-led in the usual=manner' in -accordahce with the pulse rate of the radarapparatusandthe sweep of the scanners, so as to cause bright spots to appear on the-face thereof in positions corresponding to the azimuth and'the "distanceof: the objects relative to the airplane. Since each radar scanning .unit coversonly (about; 180", in azimuth, a single P.'"P.TI. scopecambe employed-with each unit producingitsindications infthe .eorrespondi semi-circular sector57,i58 of the'faceiof thescope.

. .Ih'e reflected pulses detected by eachsscannersarefalso ,japplied toia'nother scope or 2'61, termed .ajC-scope, one C=scofpe being provided for each of the radarmnits. tTheseic-scopes'm, '61 are controlled, also.:.in a wellknownimanner, in accordance withlthe sweep andthe nod .ofithmassociated scanners, so that-a vbrightt-sp'o'twill appear on-the surface thereof at a point displaced-horizontally from azre'ferienc'e-line'Ito-fan extent corresponding ;to.:the :azimuthof-the object relativelto the airplane,-..and displaced vertically from a second reference j-lline'lto an extent corresponding to the angular elevation of "the 'object relative to the airplane.

If desired, a suitable manually variable range gate 62 or 63 may be provided between each radar apparatus and its associated C-scope so as to pass only those reflected pulses corresponding to objects lying generally at a preselected distance from the airplane, to the C- scope. Such a range gate is arranged to be conductive only during a certain portion of the radar pulsing cycle, thus allowing only those reflected pulses received during this portion of the cycle to pass therethrough. The purpose of such a range gate is to minimize the amount of random noise that will be applied to the C-scope and which might otherwise tend to mask a pulse reflected from an actual target.

The orientation of the scanners so that the sector scanned by each extends across the axis of the fuselage as above described is an important factor in fulfilling the desired objectives. It is most vital that the radar scanning be particularly eifective in the areas directly ahead of and directly behind the airplane, particularly the former, since the minimum time in which to prepare for defense occurs when substantially head-on interception is attempted by enemy aircraft. Since the sensitivity of both the scanning mechanism and of the indicating scopes associated therewith is quite apt to drop off radically adjacent the fringes of the sectors covered thereby, it is desirable that these fringe areas be angularly displaced as far as possible from the axis of flight to insure that enemy aircraft in the vital area generally ahead of the airplane will be quickly and certainly detected. By orienting the scanners as described, so that the sectors scanned pass close to, but without hitting, the corresponding ends of the fuselage, the insensitive fringe areas are placed well away from the vital fore and aft areas. Moreover, by so orienting the scanners, it is possible to scan a full hemisphere through the generally conical end portion of the unit without requiring that the associated randome project outwardly from the wall of the unit to interfere with the desired smooth streamlining of the unit.

Also, by forming the central portion of each unit as a barrel-type gun turret, providing for fire coverage over a relatively large sector about the airplane, it is possible to make the end portions of the unit substantially symmetrical and of a contour ofiering extremely low drag,

since but a relatively small conical sector of fire coverage is *reqtiireo robe furnished by the:ttrrretin'the tipaofithaone end-portion; ermitting arolativ'ely small, wen-streamdined construction. Thus it ispossihle to orient thesu'nits oppositely on thewingztips so as to provide full spherical iire -=and radar coverage: and r yet the drag of al the 'atwo -units-= willibe substantially eqltai, l'fibviously any a'ppreeiable difierence "in "drag produced :by units mounted, at the 'tips of the wings -asare-1tliose of this invention, feould not be tolerated; asit would result in: an 'objection- -able y'awing I moment-on ":the airplane. With fth'e; arrangenrent disclosed not only is the actual valueiof dragkept relatively low; but: it: is; substantiaily. equal atboth-ravi I tips, thfls minimizing any rsuchsadverseayawingitendeney.

i lt should be noted thalt whiletdefinite :angnlar relation- "ships ha'veib'eeh included in the drawing; andt description, these are a merely for ipurpos'es ofiilustratiomvnotof; limitation, and obviously:LconsiiierabIe-Nariation fromfztheiexact-angles indicated is-rpossible' avi'thout departingsfrom the principle of operation of the invention.

-'Wh'ere, in -the dfiSCKiPfiOIL and: ChiIDSp-Sllfihl terms as )verticat T01" horizontar have; been Jused; :they.- area-intended 7 tonefer; to theaconditionst-when thetairpla'ne iszzin inormal, --horizontalifiightposition; -=While:but one iembodiment of the presentinven'tionqhas beentspecificallyrdescribed; itsisaobvious that manyehangcs andzeshbstitutionszcan rberrmade withoutrdepartingsfrom :the. .spiritsand: scope. of thetinvention ,xas..- set.. forth .iimthe appended-claims.

.rWe claimas-our invention: v j ,1 In combination; withiameairplane;having-ta, fuselage and. .ings; extending-laterally therefromaazdefensive unit carried at the tip of each wing thereof and each comprising an elongated streamlined housing extending generally parallel to the longitudinal axis of said airplane, each of said units including a generally conical end portion including a radome forming one end of said housing, a

second generally conical end portion including a gun turret mounted in the tip thereof for restricted swinging 40 about perpendicularly related axes and forming the other end of said housing and a barrel-type turret mounted between said end portions for angular movement about the longitudinal axis of said unit and forming the central portion of said housing, search radar apparatus including a scanner housed in said first-mentioned end portion of each of said units and adapted to substantially completely scan, through said radome, the hemispherical sector of space extending outwardly from said airplane and lying to one side of a vertical reference plane passing through said scanner and intersecting the longitudinal axis of said fuselage beyond the corresponding end thereof, the units being reversely arranged on said wing tips so that the tip turret of one of said units is directed generally forwardly while that of the other unit is directed gener ally rearwardly of said airplane, and so that said scanners are so oriented that their reference planes lie substantially parallel whereby generally opposite and complementary herispherical sectors will be scanned thereby. 2. In combination with an airplane having a fuselage and wings extending laterally therefrom, an elongated streamlined unit carried at the outer end of each wing, said units including gun turrets adapted to provide full spherical gun fire coverage about said airplane, the forward end of one of said units, and the rearward end of the other of said unit-s being formed as radomes, a radar scanner mounted in the corresponding end of each unit in position to scan, through said radome, a substantially complete hemispherical sector of space about said airplane, said scanners being so oriented in said units that relatively opposite sectors will be scanned thereby and whereby said sectors will extend across the longitudinal axis of said fuselage beyond but adjacent the corresponding ends thereof so that the airplane will lie entirely between the sectors scanned.

3. In combination with an airplane having a fuselage coverage about said airplane, the opposite conical end portion including a radome and a radar scanner completely housed therein in position to scan, through said radome, a generally hemispherical sector of space about said airplane, said scanner being so oriented that the sector scanned thereby will extend across the longitudinal axis of said fuselage beyond but adjacent the corresponding end thereof, with the airplane lying entirely outside of the sector scanned.

4. In combination with an airplane having a fuselage and wings extending laterally therefrom, an elongated streamlined unit carried at the tip of each wing of said airplane, said units having their longitudinal axes substantially parallel to the longitudinal axis of said fuselage, each of said units comprising generally symmetrical conical end portions and a central portion carried therebetween and constituting a barrel-type gun turret rotatable about the longitudinal axis of said unit, one of said conical end portions including a second gun turret in the tip thereof adapted to provide with said barrel-type turret at least hemispherical fire coverage about said air "s plane, the opposite conical end portion including a radome andairadar scanner completely housed therein in position to scan, through said radome, a generally hemispherical sector of space about said airplane, saidscanner being so oricnted that the sector scanned thereby will extend acrossthe longitudinal axis ofrsaid fuselage be yond but adjacent the corresponding end thereof, with the airplane lying entirely outside of the sector scanned,

,the units on opposite wings being relatively reversely arranged, whereby to provide full spherical fire and radar coverage about said airplane. I

References Cited in the file of this patent UNITED STATES PATENTS 2,377,073 Eaton May 29, 1945 2,407,451 "Reiniger Sept. 10, 1946 2,454,806 Kemmer et a1 Nov. 30, 1948 2,463,233 Alexanderson Mar. 1, 1949 2,472,136 Whitlock June 7, 1949 2,520,166 Page Aug. 29, 1950 2,524,702 Hansell Oct. 3, 1950 2,570,251 Lester Oct. 9, 1951 2,572,127 Field et a1. Oct. 23, 1951 2,573,021 I-Iiginbotham Oct. 30, 1951 2,654,083 Lange Sept. 29, 1953 V OTHER REFERENCES Aero Digest magazine, issue of December 1 1945, pages -51 

